Single serving quiches and grain-free options abound on the internet but most of them don't really suit me. Either they aren't really quiche or they aren't really crusted, more like baked scrambled eggs or a tart-crust that doesn't work so well with savory quiche ingredients. I've also seen options that use bacon or ham as the crust but neither of those are dry enough to create a good crust. Ham gave me a soggy-bottomed product and bacon shrunk up too much, letting the quiche leak out to engulf the meat. Prosciutto shrinks but not so much and doesn't add much of its own liquid to the quiche. As long as the prosciutto lines the baking dish completely without tears, the egg custard is well-contained.
Another problem plaguing the recipes I found online were the wild variations in egg-liquid-fat proportions. Some were all egg; some were mostly cream. And some used low-fat milks and egg whites for "healthy quiche" that just made inedible food-like substances. I often found myself running out of custard when filling different sized tins and having to guess-timate how to make up the difference. I needed to find a way to make a little or a lot of custard and know that it would still taste right. I searched classic recipe sites and older cookbooks for the right proportion of egg to dairy that would provide the rich creamy custard but remained adaptable to any size quiche.
Classic Quiche Ratios
1 egg : 1/2 C dairy : 1/3 C cheese : 2/3 C filling
For every egg, use 1/2 cup dairy (preferably full-fat or more), 1/3 cup cheese, and 2/3 cup of meat or vegetable fillings. Fillings can be any kind of cooked meat or vegetables: most commonly bacon, ham, or sausage, mushrooms, onions, greens, and fresh herbs. Asparagus, peppers, zucchini, tomatoes, broccoli, leeks, pretty much anything. Traditionally, quiche was a means of cleaning up leftover foods. It is only important that everything be cooked to remove the liquids from the foods that would compete with the custard. Fillings should be fairly dry to keep the quiche from sogginess.
Made in a jumbo muffin tin, these mini quiches are the perfect size for a hearty brunch. For smaller appetites, the regular sized muffin tins are a better option. I would also assume that this quiche could be made in a traditional 9-inch pie tin but I haven't tried it myself.
To make the pictured quiches, use a jumbo non-stick muffin tin. Do not grease or line with muffin cups. The combination of non-stick pan and prosciutto works just fine. I haven't tried this recipe without a non-stick pan.
Thinly slice 16 ounces of white or brown mushrooms and sauté in butter. When they are nearly done, add 1 clove garlic, minced, and the finely sliced whites and the sturdier greens of 3 or 4 scallions, reserving the thinner greens for later. Sauté the onions until translucent and the mushrooms are crisp on the edges. Remove to paper towels to drain. Julienne or finely chop a handful of fresh green herbs or baby spinach. I think I used chives and spinach here. Keep the uncooked greens to no more than a 1/2 cup or they will add too much liquid to the custard. The total volume of prepared filling ingredients should be 2 cups.
Grate 1 cup of peccorino romano. It is a very dry cheese so it keeps the quiche less soggy. Other cheeses can be used but softer ones may create a bit more wetness and need a little longer to bake. Romano or Parmesan also brown nicely on the top of the quiche.
In a pourable bowl, whisk 3 eggs, 1 cup whole milk, and 1/2 cup cream. Salt to taste, about 1 teaspoon, and a few grinds of black pepper.
I use prosciutto from Costco that comes in a double 12-ounce pack with 24 slices in each pack. This recipe will use 12 ounces/about 24 slices of prosciutto. Cut the whole stack of slices in half the short way. Then arrange 3 or 4 half-slices of prosciutto in each muffin cup to line the sides and bottom completely. Some shrinkage will happen so make sure that the prosciutto stands up a bit over the top of the cup. These paper-thin slices tear easily so work carefully and layer as needed to cover holes.
Add the mushrooms, scallions, and herbs or spinach, about 1/3 cup total, to each prosciutto-lined cup. Add about 2 tablespoons grated cheese to each cup, on top of the fillings. Fill each cup with the egg custard. Add a bit of herbs, greens, or scallion rings to the top.
Bake at 350F for 35-40 minutes until the centers of the quiches are set and won't stick to a sharp knife inserted in the center. There may be a bit of wobble. Don't overcook. Remove and cool in the pan for about 15 minutes. Gently slide a wooden skewer or other non-stick-safe utensil around the quiches to separate from the pan. Lift carefully in case some custard leaked (which is very likely) and stuck to the bottom. If the eggs were fully set in the baking, they won't stick badly and will remove easily with careful treatment. Makes six.
Serve warm or cold with salad for brunch or supper, or with fruit and bread for breakfast. To serve at a later time, cool completely on a rack and refrigerate in a covered dish. Reheats well in a microwave with a damp paper towel in 60-90 seconds.